Cross-Flow Filter Screen Slot Geometry for Particle Rejection
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Solution Overview
Problem
Existing cross flow filtration methods face challenges in efficiently rejecting small particles from water, often requiring high energy consumption or difficult membrane manufacturing processes.
Innovation Solution
A filter screen with specifically arranged slots, where each slot has a longest principal axis of 800 micrometers or less and a second axis perpendicular to it, is used. The slots are arranged in rows and columns with defined distances, allowing for improved particle rejection without the need for high water velocity or reduced slot width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the velocity at which water flows over the surface of the membrane is increased to increase rejection of small particles, then particle rejection is improved, but energy consumption increases and membrane wear increases
Solution Approach 1:
The patent changes the geometric parameters of the filter slots (length L ≤ 800 μm, width W, spacing XP ≤ 350 μm, spacing YP) to achieve enhanced particle rejection at lower flow velocities. By optimizing these dimensional parameters, the filter achieves high rejection efficiency without requiring high cross-flow velocities, thereby reducing energy consumption and membrane wear.
2Reliability
If membranes with smaller slots are manufactured to reject smaller particles, then particle rejection is improved, but manufacturing difficulty increases and throughput is reduced
Solution Approach 1:
The patent specifies precise parameter ranges for slot dimensions (L ≤ 800 μm, XP ≤ 350 μm) that balance manufacturing feasibility with filtration performance. These parameters are optimized to be small enough to reject fine particles (5-100 μm) while remaining large enough to maintain acceptable throughput and be manufacturable using conventional techniques.
3Reliability
If the slot width is reduced to reject smaller particles, then particle rejection is improved, but the throughput of the filter is reduced
Solution Approach 1:
The patent optimizes the slot width parameter W to achieve a balance between rejection efficiency and throughput. The width is reduced sufficiently to reject particles in the 5-100 μm range while maintaining adequate opening area to preserve filter throughput and prevent excessive pressure drop.
Solution Approach 2:
The patent addresses the throughput-rejection tradeoff by optimizing the two-dimensional slot geometry (length L and width W) and their arrangement (spacing XP and YP). By carefully controlling the aspect ratio and spacing, the filter achieves high rejection of small particles while maintaining sufficient open area for adequate water throughput.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances the filtration process by effectively rejecting particles with smaller diameters, resulting in a more purified permeate and reducing energy consumption and membrane wear.
Implementation Method 1
cross flow filtration, in which water passes across the surface of a filter medium. Some of the water passes through the filter medium and is eventually collected as the permeate, which is accumulated as purified water. Large particles fail to pass through the filter medium and remain in the water that is passing over the surface
Data Source
AI summary
A filter screen for cross-flow filtration includes a cross-sectional thickness measured from an outer surface to an inner surface, the outer surface configured to exclude particles; and a plurality of slots that are evenly spaced apart. Each of the slots have a length along a longest axis at the outer surface; a width measured from a perpendicular axis relative to the length at the outer surface that is less than the length; and a depth along the cross-sectional thickness that is tapered.